


When Two Becomes One

by LyraWrites



Category: Haikyuu!!
Genre: Alpha Oikawa Tooru, Alpha/Beta/Omega Dynamics, Alpha/Omega, Angst with a Happy Ending, Consensual Sex, M/M, Omega Iwaizumi Hajime, Porn With Plot, Porn with Feelings, Possessive Behavior, Possessive Oikawa Tooru, Pre-Relationship
Language: English
Status: Completed
Published: 2020-10-23
Updated: 2021-01-01
Packaged: 2021-03-09 06:35:10
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,224
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27159401
Author URL: https://archiveofourown.org/users/LyraWrites/pseuds/LyraWrites
Summary: Iwaizumi and Oikawa are sex friends, however Iwaizumi refuses to 'to go all the way' with Oikawa wanting to save himself for a person that he truly loves and a person that loves him in return. Oikawa being a respectful alpha never pushes Iwaizumi but an ill timed meeting with Kageyama forces him to reveal his true feelings.
Relationships: Iwaizumi Hajime/Oikawa Tooru
Comments: 14
Kudos: 154





	1. Walls outside of the court

Iwaizumi would never admit it, but he loved the feel of Oikawa's dick in his mouth. It could be that his best friend was an alpha though and it was his omega nature. He couldn't be 100% sure as he never had played around with anyone else other than Oikawa. But he loved having his friend tied with his hands behind his back, helpless while he was bringing him to the peak. He couldn't trust his friend to not spurt all over him to mark him away from others. In the heat of the moment alphas do stupid things. It would be very annoying to try and get the scent off and have others poking around seeing who "his" alpha was, when there was no such thing. 

He loved looking at Oikawa seeing the moment that when the wet heat of his mouth met the alpha's penis. Often he would be forced to close his eyes, mouth open in a pant, his head leant back. A moment of pure ecstasy. However, at that moment, he was usually not more than half mast. 

Iwaizumi could still fit him into his whole mouth. But he would start with the tip, swirling his tongue, before apply a little more tongue pressure. Oikawa usually groans a little, and sometimes, he does put a gag on him. However, today's moans egg him on, Iwaizumi feeling it twitch in his mouth and grow, moves his mouth further down to where the knot is just starting to form. With the tip of his tongue he massages where knot meets penis. Today Oikawa's hips buck and he makes a keening noise. God he was erotic like this. 

He disengages his mouth, Oikawa letting out a small whine. He doesn't wait for long however before Iwaizumi is licking and kissing the knot, applying gentle pressure. 

"Oh shit! Please more!" 

Iwaizumi complies, bringing his hand to the otherside, where his mouth is absent, stroking and toying with Oikawa's developing knot. Feeling the skin stretch and swell; there is heat there. Iwaizumi loves the heat it gives off. He imagines it entering him and how lovely it would feel, filling him completely, unable to break away. An intimacy unparalleled. For now though, he focuses on the feel of it with his mouth. 

The knot and penis has swollen to roughly its full extent and Iwaizumi stuck out his tongue and drew a lazy line from base to head with it, not quite touching the head. He skirts around the head, while making an "O" with his index finger and thumb, Oikawa's penis in the centre. He pushes down on the knot, but only lightly, not having the knot break through, simulating the feeling of almost entering him. 

A low growl came from Oikawa's throat, and their eyes met. Pure and unbridled last met his gaze, goading him on. Delicious heat pooled in Iwaizumi's stomach. He loved it when he could get Oikawa on the knife edge like this. It added to the fun of him wanting but helpless to control where he got his pleasure from. 

Taking pity on the prone alpha, Iwaizumi engulfed the head of his dick simultaneously pushing his fingers over the knot so that "O" was below it. 

"Ah fuck! Iwa!" Oikawa thrashed underneath him and Iwaizumi had to pin his hips to stop him from moving. Once Oikawa calmed he decided that it was enough playing around. Iwaizumi hollowed out his cheeks and start lowering and rising. His tongue swirling and pressing at sensitive spots. The dick in his mouth hard and twitching. He could taste precum when he swirled his tongue over Oikawa's penis head. This was met with growls and cursing. 

He brought his second hand to gently tug and pull at the knot below. Occasionally he would use it to fill the gaps where his mouth couldn't reach. 

Oikawa on his part was reduced to a series of guttural growls and dirty talk. He was close, he always became a bundle of instincts ridden flesh when he was close. Telling him how good he was, that he was Oikawa's, how he would mark and fuck Iwaizumi that everyone would know have no doubt. Iwaizumi was drowning in his words. It was  
becoming harder and harder for Iwaizumi to not touch himself. Somewhere in his omega brain, loved the idea of being claimed, fuck raw, possessed so utterly by this alpha. 

Lost in Oikawa's dirty talk, he was surprised when he pulled away, a loud, sinful squelch penetrating the air. Shit, he should have known. He quickly moved his mouth back on to the penis, the moment he did cum flooded his mouth. He looked up to meet Oikawa's eyes and saw not only euphoria but something dark as well. 

Unable to take the sight for long, Iwaizumi grabbed the tissue box. "Nice try, shittykawa." Iwaizumi says with no real heat after spitting out the cum in mouth into a bunch of tissues. He binned the tissues and began untying Oikawa. Unconsciously gently rubbing the red flesh. 

"So mean Iwa-chan! Why can't I cum on you? I promise to wash you thoroughly afterwards." Oikawa sang spoke while turning around to look at Iwaizumi. 

With a flick to his forehead, Iwaizumi said, "pervert." Before moving to sit on the floor. It was a bit too intimate to be sitting on the same bed together after what had just happened between them. 

"You are the one to talk! After doing all those erotic things to me! I feel taken advantage of! I am more than just a penis." Oikawa moaned before draping himself over his back. 

"I don't want to hear that from Mr. Fanclub!" His irritation rising. 

Arms wrapped around his upper body in a loose hug. "There is no one but you, Iwa-chan! You know that!" His arms hugged tighter and crept up. "So why don't you give me your first time~" arms tightened and climbed again. "I promise to be gentle~" The force and positioning of the hug meant Iwaizumi was being choked. 

Iwaizumi broke the hug! "Stupidkawa! Be more conscious!" With that Iwaizumi punched Oikawa on the head. 

"Wah! I provide Iwa-chan with a service and this is what I get? None of Oikawa-san's previous girlfriends get to see this side of him. So meeean!" Oikawa pouted. 

"Oi! Who is providing who a service?! And the next time you get yourself a girlfriend be a little more serious and maybe they will!" Iwaizumi raged, contemplating a second punch. 

"Noooo, that's too much trouble. Why should I when Iwa-chan would just accept me for me~" Oikawa had the indecency to wink. 

"You-! Trashkawa! Lazykawa! No one is accepting anything!! I am going to the bathroom," with that he stomped out of Oikawa's room. 

Once he got in the bathroom, he turned on the tap and threw a face towel in the basin. Iwaizumi sighed, and leant on top of said basin. His face felt hot. Stupid, idiotkawa and his blabber mouth, completely ruining whatever mood he had from the blowjob. It was tough having a best friend like Oikawa, tougher still when he had a small crush on the other. He suspected that sometimes Oikawa knew hence the teasing, but he hoped that if Oikawa actually knew that he was a good enough friend to back off if he really knew about it. He tried not to linger on those thoughts though. There was no point lingering on it. It didn’t change the fact that his heart was racing. 

Exchanging hand and blowjobs was enough for Iwaizumi. Despite the previous nagging by Oikawa to go further, Iwaizumi had explained it a bunch of times to Oikawa before. Why Iwaizumi won't do that with him. It was different for the person being entered, there was a vulnerability that he could not explain. He wanted to share that moment with a partner, a boyfriend most likely. Not someone who will jump onto the next thing that presented itself. Oikawa, probably wouldn't be a dick about it, but he wanted that intimacy between romantic partners first, and not just something to tick off a made up check list. 

Besides, if Oikawa really wanted more, he would just go 'all the way' with one of his girlfriends/boyfriends, and that will be the end of that. Iwaizumi will most likely get an alpha boyfriend in uni and go 'all the way' too. Their time in high school will one day fade into fond memories and maybe eventually forgotten. 

Ouch, that stung a little. Turning off the tap and draining the face towel, Iwaizumi then slapped it on his face. He appreciated the heat and feeling of cleanliness. What was that about not lingering around certain thoughts? Once the heat faded a little from the towel, Iwaizumi washed his face and hands properly before returning to Oikawa's room. 

"Iwa-chan! Which starting formation do you like better?" He was presented with two bits of paper. And just like that, things fell back into place.

**Notes for the Chapter:**

> Ara, ara; it has been a while! Hope everyone has enjoyed this! This is the first time I have ever written porn *blushes* I hope I did well! BTW I have already finished writing this story but have not yet edited it. 
> 
> I just finished season one of Haikyuu last week and LOVED these two. I love their dynamic. Has all the makings of a uke tsundere and ikemen seme. Childhood best friends are also a trope I am a sucker for :P. 
> 
> Please let me know your thoughts and if I have stayed true to character!


	2. A cat playing with a mouse

'Ahh, shit', Iwaizumi cursed as a familiar tingling sensation overtook his body first thing in the morning. He wasn't due for another heat until next week, at least according to his tracker app. Stupid app. He rolled over to his bedside table, picked up his phone, grumbled as he registered "first day" on the tracking app. His app pinged, there was a notification. 

*You are a week a 3 days early. That is a significant jump. Please register if any of these events has occurred. By registering your app will be more accurate in the future.* 

Iwaizumi opened the notification and a list appeared before him to check. As expected a whole bunch of "your alpha" reasons were listed. These he ignored. He wished that he app would factor in that he was single and get rid of these options. Then a checkbox caught his eye. 

*Sexual activities with an alpha pre, during or post rut. To find out more about how an alpha you are sexually active can influence your cycle click here. * 

He was 100% sure that it wasn't during or post rut as Oikawa didn't take the time off practice/school. But could it have been pre? He was pretty sure that Oikawa should have been a little earlier though? But that didn't seem right otherwise his rut would have been this week and judging by how he was yesterday, it was just regular Oikawa. But he wasn't a creep, he doesn't exactly keep a tracking of Oikawa's rut. He decided to send a text. 

"Lazykawa, time to get up. Also, I'm creating the schedule for this month. When's your rut?" 

While waiting for the response text, he clicked the link and read it. After he read it he let out an annoyed huff. Could cycles even do that?! Apparently sometimes just being around an alpha too much the heat/rut cycles can start syncing up. Stupid evolution and the need to procreate. An alpha cannot impregnate if they aren't in a rut and an omega cannot be impregnated without a heat. It made annoyingly logical sense. Ahhh, why should his body have to operate around Idiotkawa's schedule?! 

PING! *Morning~ I feel like it should be the day after or day after that? So late this time! You sure that's the only reason why you want to know though ;) You can be my rut partner if you want. * 

Iwaizumi sat up in surprise and typed back furiously. *THAT CLOSE?! Why did you let me come over when you are that close, what if you guessed wrong?!* 

What he got back was a sad face emojis and *I'm not an animal you know? I can control myself T.T* 

True enough, Iwaizumi supposed. TV and books liked to overexaggerate the effects of ruts and heats. They don't exactly lose their minds to it, it just amplifies emotions and ramps up the want for sex. But still, it was a bit rude to not let your partner know... sexual partner... not partner in anything else... well they were pretty much partners in everything just not in romance. 

*No comment. BTW I ate something bad yesterday, don't think I can make it to school/practice today. * Like hell was he going to let Oikawa know about syncing. 

*Iwa-chan take care of your body. Your heat is in a week and couple of days right? Gotta be mindful~* 

Before he could even think he had sent, * CREEP! DIE! TRASHKAWA* 

He just got back another crying emoji. Serves the creep right. Ah, he had such shit taste in alphas. Whatever, he needed to strap himself in for this heat and got up to start making preparations. Thank god his parents were out.

It was twilight when a knock came at his door. There were faint murmurings as his mother opened the door. Iwaizumi sat up to drink water and spaced for a bit. He felt a lot better. He may need to take one or two days more off though? Maybe he should have told Oikawa about his heat? He would be better prepared for their team’s sake. As Iwaizumi went for his phone there was a knock on his door. 

“Hajime, Kageyama-kun has arrived.” 

Oh shit! He had completely forgotten! He had arranged for Kageyama to go over some old volleyball videos together. Shit, shit, shit!   
  
“Give me a sec!” He sprayed deodorant around praying that it was enough to disperse any smells and that it wasn’t loud enough to be heard from outside. Once he had, then he opened the door minimally only enough to drag Kageyama in and to thank his mum for opening the door for him, before rushing to shut it. He hadn’t told his mother as she had left for work before he awoke, and definitely didn’t want her thinking anything suspicious was going on between him and Kageyama. 

Kageyama immediately pinched his nose. “Iwaizumi senpai, it really smells strongly of deodorant.” 

Iwaizumi flushed, there was no escaping it he had to explain it to get rid of Kageyama. “Ah, sorry, I had to,” he looked away, cheeks heating up even further, “I’m in the middle of my heat.” He chanced a glance and saw the other boy’s face pretty much glow bright red. “N-not that I planned it this way or anything! My stupid body is a week early from the usual. Sorry Kageyama, I forgot to message, can we reschedule?” He practically mumbled the last part. He was going to die from the embarrassment. 

“Ah, um yeah, o-of course! Do you mind if I use your bathroom though?” This was also mumbled. 

He was going to treat this kid to some food the next time they met. His blush was kind of cute though... Oh shit. He felt his body pour out pheromones. He didn’t know why but he looked. And because he was the unluckiest guy in the world, Kageyama saw. 

“S-sorry, it’s a... biological reaction.”

He said it to the floor so seriously, Iwaizumi almost laughed. Almost. How had he never noticed how adorable Kageyama was? Ah shit, he logically knew he should be more concerned about how much pheromones he was pumping into the air, but he wanted to tease him a little longer.

“Say, Kageyama, you’ve grown a heap in this past year. Are you taller than me?”

Clearly not knowing where the conversation was going, but happy to be redirected, Kageyama swallowed and replied. “I, I think so. I’m 181 cm…”

“Ah, that’s good. You see I’ve always thought I was going to be a beta because of how tall I was, not a lot of alphas are taller than me. I was pretty surprised when I found out I was an omega.” He walked to Kageyama, as if wanting to compare heights. “I know I shouldn’t care so much, but when it comes down to it, I really would prefer a partner taller than me.” He raised his hands and placed it on top of his head and followed through, touching Kageyama’s forehead. “Ha, you really are taller than me.”

They locked eyes, he could see the nervous energy and the want hidden behind those eyes. Making an educated guess, Iwaizumi believed that he hadn’t ‘gone all the way’ either. It was comforting, in a way.

It was quiet between them, he could hear a bike stopping outside. However neither of them cared about the bike. They both were too in this bubble, the world fell away. They could feel the slow build up, the electricity that was lust in the room. Iwaizumi can smell Kageyama now, reacting to him. If you asked him at the beginning of the day, his answer would have remained as it was yesterday, he was waiting for a steady partner. But now that it was presented in front of him… “Neh Kageyama, are you in a relationship at the moment? Have you ever had sex?”

Kageyama took a deep inhale. “No to both, but I wouldn’t mind if it was you senpai,” was what was murmured into his ear.

Iwaizumi felt a hand touch his shoulder and another brought up to his chin. If this was going to be both their first time, it was a different sort of special wasn’t it? Iwaizumi would have preferred maybe a more confident hand, but he was gentle, respectful and wanting. Kageyama was a good person, would keep it between them and most importantly was serious about anything he put his mind to. He could have worse for a first time, a lot worse. It was pretty much his requests in a romance partner anyways. He didn’t want to stop what was happening between them.

Their lips met, then their tongues. Hands fumbled, roaming backs, chests, going under shirts. Touching, groping, feeling. Exhilaration was building, desperation climbing as their scents intermingled. God, why did he wait? Pressing the alpha to him, he felt his cock press against his own. They groaned into each other’s mouths. This wasn’t anything he hadn’t done before, yet it completely different to when Oikawa and he had done it. Iwaizumi pushed that thought away. He was here with Kageyama now. Kageyama who was undressing his shirt, Kageyama who was kissing his neck. So why was it, that when he opened his eyes, he saw Oikawa at his doorway? 

**Notes for the Chapter:**

> Oh hot daaang, am I mean or what? Leaving you all at a cliff hanger~ But I promise to update next week ;) Hope you enjoyed this chapter despite the cliff hanger. If you do kudos and comments give me life!
> 
> Happy Halloween!


	3. When Two Becomes One

It was pure instinct that made Iwaizumi push Kageyama away as Oikawa came into the room swinging a punch. Not making contact with his expected target, Oikawa stumbled and fell on the bed unable to stop the momentum. The glare Oikawa sent Kageyama would have killed him a thousand times if looks could kill. There was a mad fury in them that he had never seen before, even the last time Oikawa had snapped around the first year Karasuno player. It wasn’t just his self-control that had snapped, this was… something else.

Once again acting on instinct, Iwaizumi got down to Oikawa’s level forced him to look at him, while placing his hand on the other’s knee. “Oi, Idiotkawa, what are you doing? You aren’t an animal, right?” he murmured just that it was the two of them, circling his thumb in what was hopefully a comforting manner. 

There was a growl which ended in a small whine, a shuddering breath and then, “He’s the animal! Are you okay?” this was said with so much anger and desperation that his heart clenched. Who was this man in front of him? Was it really Oikawa? What was he doing? And then, softly, so softly that it sent shivers down his spine, “I will kill him if you want me to Iwa-chan.”  
  
And then it clicked. He brought his other hand to Oikawa’s hair. “I’m fine, Tooru. Kageyama-kun didn’t do anything I didn’t want.” He could feel the alpha tense under him, and then disentangled from him to stand. He was about to stand also when Oikawa’s hand found itself in his hair, stilling him from moving any closer to Kageyama.

“Tobio-chan~ my bad! I misunderstood, but Iwa-chan can’t play today, okay?” Iwaizumi looked up. His voice and tone were back to the usual stupid lilt, but his eyes still had that hard, unyielding look.

Kageyama on his part looked to him, Oikawa and then back to him. “Iwaizumi senpai, will you be okay?”

“What are you saying Tobio-chan?” The same sing song tone and then, “of course he will” in a soft possessive (?) tone.

It was clear that Kageyama wanted his reaction but before he could request it, he replied. “Kageyama, I’m fine, rain check okay?” the hand in his hair tightened, not painfully, but almost as if it was an uncontrollable reaction.

Being the good kid he was, Kageyama apologised for any inconvenience, promising to come back another day. He then left the room, shutting the door behind him meaning Iwaizumi and Oikawa were left alone. Iwaizumi breathed a sigh of relief, with the situation diffused he could send Oikawa packing as well in a few moments and finish off his –

Suddenly he found his back on the bed, his hands pinned above him. Oikawa smiling above him but it was insincere as hell. “Neh, Iwa-chan, it’s not good to play around with Tobio-chan, he takes everything so seriously” the hands tightened around his wrist, “he may get the wrong idea.”

Iwaizumi couldn’t help the blush that spread across his face. “W-what are you talking about I-idiotkawa?!”

“Ah, you are so mean to me, Iwa-chan.” Oikawa said lowering his face to Iwaizumi’s throat, nuzzling his scent glands. “Didn’t you say your first will be with a steady partner? I know for a fact that there is no way Tobio-chan could be, no way, nooo way~”

“Stop playing around and get off me!” Iwaizumi’s heart was going to burst out of his chest! Ah stupid heat, mixing his emotions up. He hated that he wanted this to be something else than it was. He hated that he could very well misconstrue this, maybe have this moment, but he would regret this moment. He needed to get Oikawa off of him, before they could do irreversible damage to their friendship.

“Iwa-chan, I wanted to be patient and for you to come to me, but you started to build walls to keep me out. Ahhh, so mean.”

Iwaizumi arched his back as Oikawa licked his scent glands. He could feel it building up again, the lust and another wave of heat. “Oikawa, please.” He didn’t know if it was to ask him to continue or to stop. A traitorous part of him really wanted this, but another part of him knew that this was something he could not turn back from. The fear jolted him out. “Oikawa, if we do this, we could never be friends again!”

The nuzzling and licking stopped. Oikawa shifted his weight and let go of his hands. He felt both relief and loss at the lack of contact, however Oikawa was still on top of him, sitting on his hips, looking at him with such a serious face that it unnerved him a little. “Hajime, would that be so bad?”

His heart was plunged into ice and his whole body tensed. “H-how could you say that!” He turned his face away, unable to accept the words he just heard.

A strong and warm hand brought his face back to meet Oikawa’s gaze. “Hajime…aren’t you ready for more?” The alpha must have noticed the confusion in Iwaizumi’s eyes. “You’re such a blockhead sometimes Hajime.” A small kiss was placed on his cheek. “I don’t want to be _just_ friends anymore. I want you with me forever. I want you to be my partner in everything. My boyfriend, my ace, my omega, my everything.”

Iwaizumi could barely register his words. What was this feeling? His body was shaking.

“Hajime?”

“Ah! Stop it with the ‘Hajime, Hajime, Hajime!’ It’s weird!!” He surged upwards to meet Oikawa in a kiss. Although describing it as a kiss would be too chaste as mouths met, tongues glided against one another, tantalising each other. When they broke for air, Iwaizumi was met with Oikawa’s smirking face.

“I thought you liked serious guys.” And proceeded to kiss down his neck, sending jolting sensations down Iwaizumi’s spine.

“…I like you best though.” As soon as he said it Oikawa froze. Urgh, he can’t believe he said it, was it too cheesy?

Oikawa brought their foreheads together and Iwaizumi found himself looking into the intense brown orbs of his eyes. “Yeah, I love Iwa-chan too.”

Iwaizumi surrendered himself to the happiness of the moment and together moved forward with their lives. When Iwaizumi was a little older, he realised that of course Oikawa was waiting for him and that he only needed to trust his alpha. After all no one loved him like Oikawa ever since they were children. The intimacy of that moment and the joy of that moment would never be replicated in their lives ever again. The moment when longing stops and partnership begins is rarely repeated in a relationship. This of course meant that more happiness to a greater degree could found, balanced of course by Oikawa’s tendency to now irritate him further. But that was a trade he was always willing to make.

**Notes for the Chapter:**

> Oh my goodness! My apologises for the wait everyone! I had this written but I stubbornly wanted to see if I could write an extra sex scene but I just didn't have it in me @@. But irregardless, I hope you enjoyed the resolution and the fic in its entirety now!


End file.
